Practice : Behaviour-Driven Development (BDD)

Purpose and Strategic Importance

Behaviour-Driven Development (BDD) is a development approach that encourages collaboration between developers, testers, and business stakeholders to define application behaviour using plain language. BDD bridges the gap between technical and non-technical roles, ensuring that software is built around shared understanding and real user needs.

BDD improves clarity of requirements, strengthens test coverage, and accelerates delivery by reducing misunderstandings. It’s an effective practice for building the right thing, the right way - with quality and alignment from the start.

Description of the Practice

  • BDD uses structured syntax (e.g. Given–When–Then) to describe behaviour in a human-readable format.
  • Scenarios are written in tools like Cucumber, SpecFlow, or Behave and run as executable tests.
  • Feature files represent desired system behaviour and are agreed upon by the team before coding begins.
  • Tests act as both specifications and documentation of the system's behaviour.
  • BDD scenarios are automated and run in CI as part of the quality pipeline.

How to Practise It (Playbook)

1. Getting Started

  • Choose a BDD tool that fits your language and ecosystem (e.g. Cucumber for JavaScript or Java, Behave for Python).
  • Start by writing simple scenarios with business stakeholders using Given–When–Then syntax.
  • Translate scenarios into step definitions that map to test logic.
  • Run scenarios in CI/CD pipelines and treat failures as product issues.

2. Scaling and Maturing

  • Embed BDD into backlog grooming, planning, and refinement sessions.
  • Use feature files as shared contracts between business, QA, and development.
  • Automate acceptance criteria and track feature completeness through BDD coverage.
  • Refactor and clean up scenarios to keep them readable and maintainable.
  • Encourage pairing between developers and testers when implementing step definitions.

3. Team Behaviours to Encourage

  • Collaborate on test scenarios before development starts - shared understanding is the goal.
  • Write clear, unambiguous behaviour descriptions that reflect user value.
  • Avoid overusing technical language - keep scenarios accessible to all roles.
  • Review scenarios regularly to ensure they reflect current product behaviour.

4. Watch Out For…

  • Treating BDD as just another test tool rather than a collaboration method.
  • Creating fragile or overly specific scenarios that are hard to maintain.
  • Using BDD in isolation - it works best when integrated into team ceremonies.
  • Step definitions becoming overly complex or unmanageable.

5. Signals of Success

  • Teams align on what to build before coding starts.
  • Behaviour scenarios are part of the delivery definition of done.
  • Fewer misunderstandings between product and engineering.
  • Executable specifications double as living documentation.
  • Product quality and customer satisfaction increase with clearer alignment.